Project description:The diversity of transcriptional programs and cellular plasticity of glioma-associated myeloid cells, and thus their contribution to tumor growth and immune evasion, is poorly understood. We performed single cell RNA-sequencing of immune and tumor cells from 33 glioma patients of varying tumor grades. We identified two populations characteristic of myeloid derived suppressor cells (MDSC) that were unique to IDH wild type glioblastomas (GBM) and absent in IDH mutant low-grade gliomas and IDH mutant grade IV astrocytomas: i) an early progenitor population (E-MDSC) characterized by strong upregulation of multiple catabolic, anabolic, oxidative stress, and hypoxia pathways typically observed within tumor cells themselves, and ii) a monocytic MDSC (M-MDSC) population. Spatial transcriptomics demonstrated that the E-MDSCs geographically co-localize with a subset of highly metabolic glioma stem-like tumor cells with a mesenchymal program in the pseudopalisading region, a pathognomonic feature of GBMs associated with poor prognosis. Ligand-receptor interaction analysis revealed symbiotic cross-talk between the stem-like tumor cells and E-MDSCs in GBM, whereby glioma stem cells produce specific chemokines attracting E-MDSCs, which in turn produce growth and survival factors for the tumor cells; in particular the FGFR1 ligand FGF11. This axis is not present in IDH mutant gliomas, associated with hypermethylation and repressed gene expression of the relevant chemokine genes. Our large-scale single-cell analysis elucidated unique MDSC populations that may facilitate GBM progression and mediate tumor immunosuppression.
Project description:The diversity of transcriptional programs and cellular plasticity of glioma-associated myeloid cells, and thus their contribution to tumor growth and immune evasion, is poorly understood. We performed single cell RNA-sequencing of immune and tumor cells from 33 glioma patients of varying tumor grades. We identified two populations characteristic of myeloid derived suppressor cells (MDSC) that were unique to IDH wild type glioblastomas (GBM) and absent in IDH mutant low-grade gliomas and IDH mutant grade IV astrocytomas: i) an early progenitor population (E-MDSC) characterized by strong upregulation of multiple catabolic, anabolic, oxidative stress, and hypoxia pathways typically observed within tumor cells themselves, and ii) a monocytic MDSC (M-MDSC) population. Spatial transcriptomics demonstrated that the E-MDSCs geographically co-localize with a subset of highly metabolic glioma stem-like tumor cells with a mesenchymal program in the pseudopalisading region, a pathognomonic feature of GBMs associated with poor prognosis. Ligand-receptor interaction analysis revealed symbiotic cross-talk between the stem-like tumor cells and E-MDSCs in GBM, whereby glioma stem cells produce specific chemokines attracting E-MDSCs, which in turn produce growth and survival factors for the tumor cells; in particular the FGFR1 ligand FGF11. This axis is not present in IDH mutant gliomas, associated with hypermethylation and repressed gene expression of the relevant chemokine genes. Our large-scale single-cell analysis elucidated unique MDSC populations that may facilitate GBM progression and mediate tumor immunosuppression.
Project description:The aim of the study is to evaluate whether the preoperative level of myeloid-derived suppressor cells is associated with postoperative complications classified by Clavien-Dindo categories. Levels of all MDSC, polymorphonuclear MDSC (PMNMDSC), monocytic MDSC (MMDSC), early-stage MDSC (EMDSC) and monocytic to polymorphonuclear MDSC ratio (M/PMN MDCS) were established and compared in patients with postoperative complications, severe postoperative complications (>= IIIA according to Clavien-Dindo) and severe septic complications.
Project description:Increased myeloid-derived suppressor cell (MDSC) frequency is associated with worse outcomes and poor therapeutic response in multiple types of cancer. In the glioblastoma (GBM) microenvironment, monocytic (m) MDSCs represent the predominant subset. However, the molecular basis of mMDSC enrichment in the tumor microenvironment compared to granulocytic (g) MDSCs has yet to be determined. Here we performed first broad epigenetic profiling of MDSC subsets to define underlying cell-intrinsic differences in their behavior and found that mMDSCs and gMDSCs display differences in their tumor-accelerating ability, with mMDSCs driving tumor growth in GBM models. Epigenetic assessments revealed enhanced gene accessibility for cell adhesion programs in mMDSCs and higher integrin b1 expression and function in mouse and human mMDSCs. Integrin b1 blockage abrogated the tumor-promoting phenotype of mMDSCs and altered the immune profile in the tumor microenvironment. These findings suggest that integrin b1 expression underlies the enrichment of mMDSCs in tumors and represents a putative immunotherapy target to attenuate myeloid cell-driven immune suppression in GBM.
Project description:Malignant glioblastoma (GBM) is a highly aggressive brain tumor with a dismal prognosis and limited therapeutic options. Genomic profiling of GBM samples in the TCGA database has identified four molecular subtypes (Proneural, Neural, Classical and Mesenchymal), which may arise from different glioblastoma stem-like cell (GSC) populations. In the present study, we identify two GSC populations that produce GBM tumors by subcutaneous and intracranial injection with identical histological features. Gene expression analysis revealed that xenografts of GSCs grown as spheroid cultures had a Classical molecular subtype similar to that of bulk tumor cells. In contrast xenografts of GSCs grown as adherent cultures on laminin-coated plates expressed a Mesenchymal gene signature. Adherent GSC-derived xenografts had high STAT3 and ANGPTL4 expression as well as enrichment for stem cell markers, transcriptional networks and pro-angiogenic markers characteristic of the Mesenchymal subtype. Examination of clinical samples from GBM patients showed that STAT3 expression was directly correlated with ANGPTL4 expression, and that increased expression of these genes correlated with poor patient survival and performance. A pharmacological STAT3 inhibitor abrogated STAT3 binding to the ANGPTL4 promoter and exhibited anticancer activity in vivo. Taken together, we identified two distinct GSC populations that produce histologically identical tumors but with very different gene expression patterns, and a STAT3/ ANGPTL4 pathway in glioblastoma that may serve as a target for therapeutic intervention. 2 samples of each variable were analyzed. Cells were cultured under normal adherent conditon (Bulk tumor cells), non-adherent plates with stem cell medium (Sp-GSC) or laminin-coated plates with stem cell medium (Ad-GSC). Xenografts were generated in NSG mice by subcutaneous inoculation.
Project description:Malignant glioblastoma (GBM) is a highly aggressive brain tumor with a dismal prognosis and limited therapeutic options. Genomic profiling of GBM samples in the TCGA database has identified four molecular subtypes (Proneural, Neural, Classical and Mesenchymal), which may arise from different glioblastoma stem-like cell (GSC) populations. In the present study, we identify two GSC populations that produce GBM tumors by subcutaneous and intracranial injection with identical histological features. Gene expression analysis revealed that xenografts of GSCs grown as spheroid cultures had a Classical molecular subtype similar to that of bulk tumor cells. In contrast xenografts of GSCs grown as adherent cultures on laminin-coated plates expressed a Mesenchymal gene signature. Adherent GSC-derived xenografts had high STAT3 and ANGPTL4 expression as well as enrichment for stem cell markers, transcriptional networks and pro-angiogenic markers characteristic of the Mesenchymal subtype. Examination of clinical samples from GBM patients showed that STAT3 expression was directly correlated with ANGPTL4 expression, and that increased expression of these genes correlated with poor patient survival and performance. A pharmacological STAT3 inhibitor abrogated STAT3 binding to the ANGPTL4 promoter and exhibited anticancer activity in vivo. Taken together, we identified two distinct GSC populations that produce histologically identical tumors but with very different gene expression patterns, and a STAT3/ ANGPTL4 pathway in glioblastoma that may serve as a target for therapeutic intervention.
Project description:Glioblastomas are aggressive primary brain cancers that invariably recur as therapy-resistant tumors. Myeloid cells control glioblastoma malignancy, but their dynamics during disease progression remains poorly understood. By relying on single-cell RNA and protein profiling, we mapped the glioblastoma immune landscape in newly diagnosed and recurrent patients and in mouse tumors. This revealed a large and diverse myeloid compartment, with dendritic cell and macrophage populations that were conserved across species and were dynamic across disease stages. Tumor-associated macrophages (TAMs) consisted of microglia- or monocyte-derived populations, with both exhibiting additional heterogeneity, including subsets with conserved lipid and hypoxic signatures. Microglia- and monocyte-derived TAMs (Mo-TAMs) were self-renewing populations that competed for space and could be depleted via CSF1R blockade. Microglia-derived TAMs were predominant in newly diagnosed tumors but were outnumbered by Mo-TAMs upon recurrence, especially in hypoxic tumor environments. Our results unravel the glioblastoma myeloid landscape and provide a framework for future therapeutic interventions.